Variability and trends in UTLS temperatures and water vapor

Thursday, 18 December 2014: 11:20 AM
Karen Hepler Rosenlof1, Birgit Hassler1,2, Ryan R Neely III3, Sean M Davis4 and Dale F Hurst4, (1)NOAA ESRL CSD, Boulder, CO, United States, (2)University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences - CIRES, Boulder, CO, United States, (3)National Center for Atmospheric Research, Advanced Studies Program, Boulder, CO, United States, (4)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States
A body of work has shown that there are trends and variability in stratospheric water vapor closely related to variability in tropical tropopause temperatures, upwelling variations, the quasi-biennial oscillation, and possibly volcanic aerosol loading and sea surface temperatures. Prior studies have also shown that stratospheric water vapor has a small but non-negligible effect on global radiative forcing; therefore it is key to understand both trends and long-term variations. In this presentation, we will examine both the relationship between tropical tropopause temperatures and stratospheric water for the time period where we have global lower stratosphere water vapor measurements (primarily since the early 1990s), as well as the relationship between tropical tropopause temperatures and assorted atmospheric indices for the longer time period where we only have temperature measurements. We will also present inferences on water vapor stratospheric trends and variability from mid latitude ground based balloon measurements, and results from climate model runs testing the impact of volcanic aerosol loading on UTLS temperatures and stratospheric water vapor.